Bullet traps per se are well known devices which have been used for many years by firearm manufacturers and users (the latter including firing ranges operated by military installations, police departments, rifle and pistol clubs, and the like) who are faced either with the need to proof, function fire and target firearms such as handguns, rifles and shotguns or with the task of simply collecting spent bullets fired on the range. In this context, "proof" means test firing a firearm at a higher load of ammunition, usually 40% greater, than the regular load specified for the barrel of that firearm; "function fire" means test firing the firearm through its full cycle of functions; and "target" means test firing the firearm for accuracy. The objectives of such devices have been to provide means located at a relatively short distance from the shooter to catch the lead or other types of bullets (jacketed or unjacketed) and prevent either the ricochet of a whole bullet or a large fragment thereof or the backsplattering of numerous small metal particles, which could return with enough energy to cause injury to the shooter or innocent bystanders, and to collect the waste lead, brass and jacket material. The known types of bullets traps have run the gamut from wood boards to sand-filled boxes to metallic funnel and deceleration chamber combinations, and their structural and functional characteristics as well as their drawbacks and disadvantages are set forth in the aforesaid prior application Ser. No. 627,705, to which reference may be had for the relevant details.
The bullet trap according to the invention disclosed in application Ser. No. 627,705, is designed to overcome those drawbacks and disadvantages and to be used with all types of manual firearms (including handguns, rifles, shotguns, elephant guns, and the like) and with all types of ammunition (up to and including armor-piercing bullets). To this end, the trap (like many of the known "funnel and chamber" types of traps) has a first pair of spaced flat metal plates located on opposite sides of the path of flight of a bullet being fired into the trap and a second pair of spaced flat metal plates arranged transverse to the first plates on opposite sides of the bullet flight path, with the two pairs of plates defining the respective sides of a passageway having at its front end an entrance opening and at its rear end an exit opening or throat through which the bullet can pass, and a spent bullet deceleration and energy-dissipating chamber the circumferential boundary wall of which is of generally spiral configuration and the opposite end walls of which are constituted by portions of the respective second plates, with the passageway communicating with the chamber substantially tangentially of the latter through the throat. In that trap, the basic novel features are that:
(a) the two first plates are made of 5/8-inch to 3/4-inch thick sheets of high tensile steel, are located, respectively, above and below the path of flight of the bullet, and in order to minimize bouncing of the bullet are oriented at respective angles of inclination to the horizontal ranging from 0.degree. to about 7.degree.;
(b) the bullet deceleration and energy-dissipating chamber has a substantially horizontal axis, and the circumferential boundary wall thereof is defined by a curved extension of the lower one of the two first plates, with (i) an initial part of the chamber wall extending from the lower first plate generally rearwardly of the passageway first at an orientation to the horizontal substantially the same as that of the lower first plate and then arcuately upwardly relative to the latter, (ii) a middle part of the chamber wall extending arcuately from the initial part of the wall generally frontwardly of the passageway first upwardly and then downwardly, and (iii) a terminal part of the chamber wall extending arcuately from the middle part of the wall downwardly and again generally rearwardly of the passageway into substantially coplanar relation with the upper one of the two first plates and into overlying relation, at an end edge of the terminal part of the wall, to the region of the initial part thereof which is contiguous to the lower first plate;
(c) the chamber has no part the radius of curvature of which is less than 28 inches, which has been empirically determined to be appropriate to keep the maximum amount of the side of the bullet presented to the chamber wall during its travel along the initial part of the latter so that the shock of the bullet is distributed more evenly along the wall and over a larger surface area thereof and that tumbling of the bullet because of its nose digging into the chamber wall (which would occur were the radius of curvature of the wall smaller than 28 inches) is prevented; and
(d) a spray nozzle arrangement is provided in the deceleration chamber for directing a liquid white water lubricant (consisting of, for example, 4 parts water and 1 part mineral oil) against the interior surface of the circumferential boundary wall of the deceleration chamber so as to flow downwardly into the passageway through the throat thereof and then along the lower first plate to a collecting vessel, for both (i) minimizing the metal to metal contact between the bullets and the metal surfaces along which they move, with the result that scoring and erosion of those surfaces as well as the generation of lead dust, if the bullets are made of lead, are reduced as far as possible, and (ii) ensuring that shells, casings, spent bullets, any lead dust that is generated, and even any fragments of a larger size that might split off from the bullets, are engulfed in the liquid and are flushed thereby along the lower first plate of the passageway and into the collecting vessel, with the spray nozzle system being interconnected with the collecting vessel by suitable piping and a pump so that the liquid lubricating fluid, after separation of solids therefrom, can be recirculated from the collecting vessel to the spray nozzle conduit.
The advantages of the bullet trap according to the invention disclosed in application Ser. No. 627,705 are manifold. Very significantly, the trap is relatively inexpensive to manufacture, can be constructed for transportability and ease of installation, and does not require the provision of thick walls, sand mounds or like back-up structures. Also, the trap is multi-functional and permits proofing, function firing and targeting of handguns, shotguns and rifles (including high powered rifles) in one system, so that expenses that might have to be incurred in connection with the known types of bullet traps for providing duplicate separate systems for function firing, targeting and proof testing can be avoided. Moreover, whereas for safety reasons high powered rifles conventionally are test-fired only at outdoor long-distance firing ranges, the use of this trap permits test-firing of such rifles to be safely performed even in a relatively small room with a distance of only 75 feet or less between the muzzle of the gun and the trap. Also, since the trap can withstand even such high energy ammunition as 30.06 NATO armor-piercing bullets, 600-grain elephant gun bullets, and the like, wear and tear on the trap, maintenance requirements, and the need for periodic replacement of parts of the trap (in particular the upper and lower impact plates of the passageway and the circumferential boundary wall of the deceleration chamber) and the attendant costs thereof are all greatly reduced if not eliminated altogether. Still further, when a bullet is fired into the trap, any lead dust generated in the course of the movement of the bullet along the metal surfaces of the trap is inevitably, and without any possibility of escape from the system, engulfed by and entrapped in the liquid lubricant fluid sprayed out of the spray nozzles and continuously flowing downwardly over the chamber wall and from there on over the lower plate of the passageway, so that the lead dust is flushed by the liquid into the collecting vessel, where it settles out of the liquid and accumulates on the bottom of the vessel and hence cannot be dispersed from the vessel into the surrounding atmosphere. The so-achieved salvaging of the heretofore normally wasted lead dust for reuse in making bullets provides an economic benefit as well, which has not been achievable with any of the known bullet traps.